Method and apparatus for forming briquettes



Feb. 13, 1951 v s. K. WELLMAN METHOD AND APPARATUS FOR FORMING BRIQUETTES 'r She ets-Sheet v 1 Filed April 1, 1947 INVENTOR BY J4. W

fie NEY Feb. 13, 1951 s. K. WELLMAN METHOD AND APPARATUS FOR FORMING BRIQUETTES Filed April 1, 1947 7 Sheets-Sheet 2 INVENTOR BY W A'I'I'O NE Y Feb. 13, 1951 s. K. WELLMAN, 2,541,899

wzmon AND APPARATUS FOR FORMING BRIQUETTES 7 Filed April 1, 1947 7 Sheets-Sheet 4 INVENTOR ATTORNEY Feb. 13, 1951 s. K. WELLMAN Y 2,541,899

METHOD AND APPARATUS FOR FORIING @RIQUETTBS 9 9/ 90 A a ta F1 EE INVENTOR J/w WWW Patented Feb. 13, 1951 1 METHOD AND APPARATUS FOR FORMING nmouerrns Samuel K. Wellman, Cleveland Heights, Ohio, assignor to The S. K. Wellman Company, Cleveland, Ohio, a. corporation of Ohio Application April 1, 1941, Serial No. 738,677

. Claims.

The invention relams to the briqueting of loose materials and particularly of finely divided granular materials:

' In the production of briquets of certam types, such for example, as metallic or partly metalhc facings for' bearings, clutches and brakes, it isbriqueting die or mold and spreading it uniformly in the die cavity preparatory to compression- The method and apparatus disclosed in United States Patent No. 2,240,971 represents the best practice available prior to the present invention. a

It is an: object of the invention to provide an improved method of charging briqueting dies capable of producing briquets of highly uniform density and susceptible of being carried out by automatic apparatus of high production capacity.

Another object of the invention is to provide improved automatic briqueting apparatus for the practice of the novel method.

More specifically with respect to the apparatus,

it is a further object of the invention to provide automatic. briqueting apparatus having press mechanism and coacting 'die mechanism which, together with control devices peculiar to it, is

removable as a unit from the press, so that the apparatus can readily be converted, by interchange of dies, to produce briquets of many different sizes and shapes.

The invention has for another object the provision of automatic briqueting apparatus capable of operating at high speed to produce briquets of highly uniform character.

With the last stated object in view, the invention has the further object of providing bydraulic press apparatus which is capable both of developing high unit pressures and'of high speed operation.

Still another object of the invention is the provision of a method of control for high speed high pressure hydraulic press mechanism capable of accurately regulating the maximum unit pressure developed by the press.

Other objects of the invention more or less incidental or ancillary to those stated above will 2 become apparent as the further description proceeds.

For the attainment of the stated objects the invention consists in certain method steps and apparatus which will be pointed out' and explained in connection with a preferred form of apparatus shown in the'accompanying drawings and finally defined in the claims.

Inthe drawings,

Figs. 1 and 2 are side and front elevations, respectively, of a press and die mechanism constructed in accordance with the invention, a portion of the press frame helng broken away in the case of Fig. 1 to better disclose the die mechanism.

Fig. 3 is a view on an enlarged scale partly in plan and partly in section of the cylinder block of the stripper press and of the die mechanism together with some associated parts, the top plane of the view being indicated by the line 33 on Figs. 2 and 5.

Fig. 4 is a view on an enlarged scale partly in rear elevation and partly in vertical section of the die mechanism and some associated parts.

Fig. 5 is an enlarged vertical section of the stripper press and the die mechanism, the section being taken on the line 5-5 of Fig. 1 and Fig. 4.

Fig. 6 is a fragmentary section on the line 66 in Fig. 5.

Figs. 7 to 12, inclusive, are fragmentary sec-=7 tional views of main parts of the die and charging mechanism illustrating sequential movements of the mechanism in its operation.

Fig. 13 is a perspective view of the die mechanism with some of the associated cavity-charging devices.

Fig. 14 is a view partly in side elevation and partly in section of an hydraulic surge tank employed in connection with the main press of the apparatus, a portion of the structure being broken away to permit larger scale illustration.

Fig. 15 is a side elevation, partly in section, of press regulating mechanism employed.

Fig. 16 is a diagram showing the main and stripper hydraulic presses and the die mechanism together with the associated pressure and control devices employed in the operation of the apparatus.

- Fig. 17 is an electrical wiring diagram suitable for the control devices of the apparatus.

Fig. 18 is a plan view of an alternative form of die and charging grid.

Fig. 19 is a vertical section on the line Ill-l9 of Fig. 18.

anism designated generally bythe numeral I2 and die charging devices generally designated bynumeral|3(Figs.1,2).

Press mechanism The press mechanism has a frame structure M. with a base block |5 supporting a fixed-ram I6 which cooperates with the movable cylinder H, the ram and cylinder constituting the main press of the mechanism. The ram l6 i's'formed with 4. plate 28 by removal of screw plugs28a that are provided to exclude dirt. Adjacent each corner of the die body is a gauge rod 36 adjustably threaded to base 24 and slidably engaging a hole 281) in the die body. The gauge rods 36 have their tops adjusted to the same heights as the die plunger 30 and the depth of holes 2812 thus a central passage to which is connected a liquid supply and exhaust pipe I8. Cylinder i1 carries on its top a platen block Ila.

The fixed head of the press comprises a plate It! to which is secured a cylinder block 28 which is bored out to form four cylinders 20a closed by head plate 2| and accommodating the four pistons 22 with stub piston rods 22a which extend downward through the head plate 2| (Fig. 5). Pressure liquid is supplied and exhausted through conduit 23 which is suitably connected to the four cylinder chambers. As will later appear the four-cylinder head press performs the function of stripping briquets from the forming die.

Die mechanism The die mechanism |2 comprises a base plate 24 which rests upon the platen Ha of the main press. A built-up die body structure generally designatedby numeral 25 is yieldingly supported from base 24 by four coil springs 26, 26 (Figs. 4, 5). The body structure 25 comprises a main plate 21 and a plate 28 secured on top thereof. Plate 28 is interrupted to receive a removable or interchangeable plate 29 which is recessed or apertured to form the side wall 290. of the die cavity. It will beappreciated that the die body structure thus constructed may be adapted to produce a variety of briquet shapes by simply changing the single insert 29. The bottom wall of the die cavity is formed by plunger 30 which is fixedly secured on a block 3|.which in turn is similarly secured to base 24.

- scoping movement is guided by a pair of heavy upright rods 32, 32 carried by the base and slidably engaged by bushed apertures of the body structure 25. Upward movement of the body 25 relative to base 24 is determined by limit stops in the form of four bolts 33 each adjacent one corner of the die structure. Each .bolt 33 is threaded into base 24 and has its head engaging a counter-sink in plate 21, the head having a square section to engage a similarly shaped hole in the hub of a sprocket wheel 34. A sprocket chain 35 passes over the four sprocket wheels 34 and serves to simultaneously turn all of the bolts 33 to equally adjust the limit stops. An operating knob 34a. is provided to engage any one of the sprocket wheels or its bolt 33 to facilitate such adjustment, access to the said wheels and bolts being afforded through apertures in always indicate the depth of the die cavity. Gauge rods 36 also serve as guides in the initial adjustment of limit bolts 33. Downward move- -ment of the die body 25 in relation to base 24 is limited by a series of blocks 31 carried by the base.

The top wall of the die cavity isformed by block 38 which is rigidly secured to plate 39 which inturn isbolted to the cylinder plate 2|. Block 38 is somewhat larger in horizontal section than the die cavity. Thus there is obviated a considerable amount of accurate machine work on part 38 that would be necessary in accordance with the usual practice of forming both top and bottom. walls of the die totelescope with nice fits in the die cavity, and of accurately aligning the telescoping parts. With the present construction it is only necessary that the bottom of block 38 I and thetop of the die body hav cooperating flat and parallel surfaces. 40 carried byblock 38 (Fig. 4) slidably engage the rods or posts 32 and the latter thus serve to Die-charging devices The die charging devices 3 comprise a grid structure generally designated by 42 which is slidably mounted on the top surface of die body 25. The grid comprises a rectangular frame having side bars 43, a front transverse bar 44 and a similar rear transverse bar 43' (Figs. 5, 6 and 13) The side bars 43 are drilled and slotted to receive light coil springs 45 and the ends of smoothly polished blades, 46, the springs serving to press the ends of the blades yieldingly downward in relation to the rectangular frame. The resultant upward thrust on the frame is resisted by guide rails 41 having flanges 41a which overlie the tops of the frame bars 43. A compressed-air reciprocating motor 48 is provided to reciprocate the grid structure, said motor being mounted on a bracket 49 carried by the body of the die and the piston rod 48a of the motor being suitably connected to the rear bar 43' of the grid.

The finely divided material to be briqueted is supplied from a large hopper 50 carried on the superstructure of the press and having its hopper bottom connected with a downwardly inclined chute 50a which in turn delivers, with automatic regulation, into the open upper end of a second inclined chute 5| which is supported from chute 50a by chain 52. The lower end of chute 5| is pivotally connected at 53 to a rectangular discharge frame 54 which is screwed to guide rails 41 and has its lower side arranged to just clear the upper edges of the grid blades 46. The chutes 50a and 5| are provided with electrically energized vibrators conventionally shown at 55 and 56, respectively. With rheostat control for the vibrators the intensity of the vibration applied to the chutes can be varied at will.

Apertured bracket arms Itwill be seen that the blades of the grid 42 divide the latter into a series of cells which can be filled from the supply chute 5| when the grid is moved beneath the discharge frame 54 and that by forward movementof the grid thus Fluid pressure supply and control devices Suitable hydraulic pressure supply and control devices are provided for the main and stripping presses as shown diagrammatically in Fig. 16. The supply conduit ll! of the main press leads to a reciprocating piston contant delivery pump 51 driven by electric motor Ml, the suction inlet of this pump is connected by conduit 58 with an upright cylindrical surge tank 59 (also shown in Fig. 14 This tank is fitted with a hollow float 60 which substantially covers the liquid surface in the tank 59 but has suificient clearance so that oil will rise around it and permit it to function as afloat. The tank is provided with a gauge glass 6| to indicate the liquid level in the tank and the top of the tank is connected to a compressed air supplyconduit 62 controlled by a valve actuated by solenoid C.

Pump 51 is bypassed by conduit 63 controlled by hydraulic valve 54 which is opened and closed by a compressed air motor 65' which, in turn, is controlled by. air valves actuated by solenoids AI and A2. Pump' 51 is also bypassed by'conduit 66 which is controlled by valve 6'! actuated by air valves controlled by solenoids BI and B2. Conduit 66 also is fitted with an adjustable spring-pressed relief valve liBadapted to permit flow from the main press to surge tank-59. An.-

other bypassing conduit 69 is fitted with relief valve I0 simply as a safety measure. Finally pump 51 is bypassed by a conduit H fitted with a check valve 12 permitting flow from the surge tank 59 to .themain press cylinder. To limit the working pressure of the main press cylinder a control device generally designated by 13 is provided. This device, which is also shown in Fig. 15, comprises a cylinder 14 fitted with an exceedingly slender plunger 15 which may be variably loaded with weights [6 which determine the pressure at whichplunger 15 and weights'lB will rise and'cause actuationof a controlling spring biased limit switch (LS6) The stripping press has its cylinder 20 supplied through conduit 23 by a, relative low pressure pump 11 driven by electric motor M2. The intake of the pump 11 is connectedby conduit 18 with surge tank I9;- Pump" may be bypassed by conduit-80 which "is controlled by valve 8| which in turn is controlled by air valves actuated by solenoids DI andD2. The'air motor 48 which actuates the charging grid of the die is controlled by a biased air valve actuated by solenoid E.

The various solenoids which have been referred to are controlled by a number of limit switches LSI, LS2, LS3, 184, and LS5 carried by the die mechanism, as shown in Figs. 13 and 16, and LS6 which is associated with the pressure control device I3. Switch LSI is supported on dis base 24 and switches LS2, LS3, LS4 and LS5 are supported on die body 25 (Figs. 5 and 13). The five limit switches mounted on the die mechthe electrical diagram of Fig. 17.

plug 82 which facilitates changing of dies. In fact a die can be removed from the press without disturbing thetiming adjustments of the controls. In Fig. 16 the dashed lines are intended only to indicate the solenoid devices with which the respective limit switches are cooperatively related. 'The main features of a suitable electric wiring system for the apparatus are shown in From the foregoing description it is believed that this diagram will be clear without detailed description.

It may be noted, however, that single letters A,

Operation In the operation of the apparatus, with the charging hopper -suitablysupplied with the loose material to be compacted, the mechanism is started by moving the selector switch (Fig. 17)

from the Oil to the Auto position. Assuming that the apparatus has been stopped in its prior operation with the charging grid in its fully retracted position (Fig. 5). the die cavity will have been .charged as indicated in Fig. 7. Also the limit switch LS5 will have been actuated at the end of the grid retraction so that at the outset of the operation the hydraulic valves 64 and 61 will be closed through the operation of solenoids Al and BI and compressed air, preferably pass conduit 1| by the air pressure.- The air pressure acts to supply a large volume of liquid through the bypass H to effect a relatively rapid traverse of the main press cylinder until the pressure in said cylinder rises to that of the compressed air sourcc, whereupon the check valve l2 closes and the remaining movement of the main press cylinder is effected by high pressure supplied by pump 5'1. The upward movement of the main press cylinder lifts the entire die mechanism until the top surface of the die body engages the bottom surface of the stationary die block 38. This arrests the upward movement of the die body 25 whereupon its supporting springs 26 are compressed and the plunger 3|! is moved. upward in the die cavity to compress the charge W shown in Fig. '7 and form the briquet W as shown in Fig. 8.

During the compression of the charge the pressure .applied'to it gradually increases and when it reaches a predetermined desired intensity, say 22,000 pounds per square inch, the weighted plunger of the; control device I3 rises and permils actuation of biased limit switch LS6 with the result that hydraulic valve 61 is opened. and the pressure in the main cylinder lowered to a suitable point determined by the adjustment of relief valve 68. Preferably this valve is adjusted to maintain a pressure of not less than 1000 anism (Fig. 13) are wired to a common coupling v pounds per'square inch. The actuation of limit .switch LS also energizes solenoid DI to close hydraulic valve 8| and apply pressure to the stripping cylinders. This causes lowering of pistons 22which, acting through thrust. rods ll,.force the die body 25 downward against the tension of' springs 26 to strip the briquet from the die cavity as shown in- Fig.. 9. The downward stripping beneath the'discharge frame u. At the same time the working conditions at the point of discharge to the grid must bekept uniform in order that the loose material shall have a substantially,

uniform density from moment to moment and from hour to hour. ,This condition is attained by maintaining a substantially uniform head on the lower feed chute SI and by the further fact movement of the die body 25 actuates limit switch I-Sl which "energizes solenoid A2 to open .hydraulicvalve 64 and completely release the pressure in the main .press, allowing its cylinder,

and-the die body thereon, to fail. .At or about the time this lowering of the die body reaches the stage shown in Fig. 10, limit switch LS4 is actuated (by engagement of its arm with sta- 1 tionary dog supported by block 38, 40) to energize solenoid E and cause air motor 48 to move the charging grid forward. The first part of this grid movement starts ejection of the briquet by the forward blade and as the'grid'movementcontinues the loaded cells thereof are brought.

directly above the-top of plunger 3ll'so that the material above said plunger is'supported on the top surface of the plunger. Fig. 11 shows the position of the parts at the completion of the forward movement of the grid and the downward movement of thedie body. Near the end of the forward movement of the grid it engages and actuates limit switch LS3 which energizes solenoid D2 to open hydraulic valve 8| and release the pressure in the cylinders of the stripping press thuspermitting the tension of springs 26 to raise the die body 25 from the position indicated in Fig. 11 to its fully raised position indicated in Fig. 12. This upward movement of that the inclination of the chute is such that flow of material is attained only by vibration of the chut structure, thus making possible a nice control of the flow by controlling the intensity of the vibration. f

The design of the cellular structure of the grid -is also important in meeting the conditions referred to; An important factoris the width of the individual cell in the direction of the grid movement. The width must be large enough so that the cell will fill freely and quickly without bridging under the relatively low eflective supply head which has been-referred to. At the same time the stated width of the cell is to be kept small enough so that in the relatively rapid movement of the grid in the die-charging operation the mass of the material in the individual cells will not be great enough to cause material to be thrown from the cells or to cause localized compacting of the material by inertia effect. The width of cell which is most suitable may vary somewhat with the character of the material to be briqueted, but generally speaking it has been found satisfactory to make the stated width of the cell approximately equal to'its depth.

Thedepth, in turn, will depend upon the thickness of the briquetto be produced and the intensity of the compacting pressure. In the prothe die body carries the charging grid upward with it and the grid blades 46 are lifted out of the uncompacted material supported on the top of plunger. 30. In this way the uncompacted charge material is introduced into the die cavity as shown in Fi 12 while the material is at all times supported by the plunger 30.- Thus there is no falling of the charge into the Cavity and substantially no rearrangement 'of different portions of the charged mass. In other words, the density of'the charge throughout the die cavity is uniform. Also, with uniform operatin conditions maintained, the densities of successive charges is also maintained equal.

At the end of the upward movement of the mold body it actuates limit switch LS2 which deenergizes solenoid E and causes the air motor 48 to retract the charging grid and cause its strike-oil. blades 46 at the front end of the grill.

to remove excess material and leave the die cavity evenly filled to the top. As the charging grid reaches its fully retracted position it again actuates limit switch LS5, thus starting a repetie tion of the cycle which has been described.

The operation of the apparatus which has been described is carried out at relatively high speed, it being possible to produce up to 750 briquets per hour, and such high working speed has important significance with respect to the design of the apparatus. .The high speed possibilities of the type of electrical controls employed is known by those familiar with such devices; but the attainment of speed such as that noted involves additional considerations of importance. The design of the charging apparatus is of primary importance in this connection. The supthe following composition:

- Per cent Cu 70.9 Pb 10.9 Sn 6.3 Graphite 7.4

Air-blown .silica 4.5'

duction of friction facing briquets such as were referred to at the outset a typical material is of In the compacting of such material under a pressure of 22,000 pounds per square inch, with the loose material supplied to the charging grid under the conditions above described, it is found that the compacting ratio is about 3 to 1, that is,-

the depth of the die cavity should be approxiply of loose material to the charging grid must 4 be free and eflective at all times in order to insure prompt filling ofthe grid cells as they move briquet.

by the grid blades overlying the cavity. Allow-' ance should be made for this, and a small excess of charging material may well be provided to.be removed by the strike oil blades as the grid is retracted. l v

Since the blades forming. the cell walls of the grid occupy space at the expense of the loose material, the blades should be made as thin as may be without loss of substantial rigidity under the operating conditions. Obviously the surfaces of the blades should be smoothto favor free entry of material into the cells andinsure ready separation of the blades from th loose material as the latter is introduced into the die cavity, and to this end the blades are given a smooth and highly polished finish,

.Another factor affecting speed of operation is the attainment of rapid movement of the relatively heavy main press cylinder. This is achieved by the combined action of low pressure air and high pressure liquid, which has been. described. The air pressure on the surge tank 59 insures a fast traverse of the main press cylinder during the first part of the compression movement and is automatically replaced by the high liquid pressure to complete the compression. The

rapid air action is made practical by the use of the surge tank float which blankets thesurface of the liquid and'prevents excessive and troublesome foaming of the oil which would otherwise occur.

sun another important factor in the attain-.

ment of the high speed operationis the method of regulating the maximum compacting pressure by the use of the weight-loaded control device. Under rapidly changing pressures at intensities as high as 22,000 pounds per. square inch, con- -ventional pressure gauges of the Bourdon tube or portion relieved at 9") (Figs. 19 and 21) as does also an annular portion at Slc surrounding the character of the briquets to be produced. Thus one piece annular briquets suitable for facing disc clutches or brakes call for special applica- 1 tion of the principles of the invention, particularly in the design of the charging grid. This is shown in Figs. 18-22 of the drawings which illustrate a die and charging grid which have been slotted portion of the insert. Furthermore the slotted portion of the insert Si is thicker than the plate 90 and as a result the said slotted portion is the only part of the grid which rests upon the flat top surface of the die, except for a pair of spring-pressed wiper blades 93- attached to the front end of the frame 89. The rectangular mouth 92 of the chute also is fitted with a pair of wiper blades 94 to engage the top of the plate 90 and insert 9|.

With the grid constructed in the manner described its weight is sufiicient to maintain good wiping engagement between the upper sides of the slotted portion of the insert 9| and the top surface of the die body. This modified grid is reciprocated, in the same manner as the grid earlier described, from the loading position shown in Figs. 18 and 19 to the dischargeposition over the annular die cavity and functions generally in the same manner as the other grid. 7 However, it is to be observed that the cell structure of the first described grid is not as well adapted to cooperate with the annular form of die cavity as is the second grid because with the first form a considerable mass of the finely divided material in the central portion of the grid does not enter the die cavity but remains in the grid to be dragged back over the material delivered into the cavitywith resultant disturbance of the material charged into the cavity, and some unevenness in the filling of different portions of the cavity. In the second form of grid by keeping the central zone imperforate this result is avoided. Furthermore, by relieving the under side of the grid so that only the slotted portions rest upon the die, the metal parts between the slots or cells act effectively as wiping blades and any slight amount of the fine material that may find its way beneath the unslotted section of the grid is accommodatedby the relief previously referred to so that there is no tendency for the grid to be lifted out of .con-

tact with the top of the die.

found satisfactory for the production of such annular briquets. Here the spring-supported die body has a lower plate 83 formed with four segmental'apertures leaving a central block 83a supported by four radiating spokes 83b. An upper plate 84 is interrupted to receive outer cavity wall section 85 and inner circular wall section 86, both sections being removably supported on lower plate 83. The bottom cavity wall or plunger 81 is in tubular form with four slots 01a to pass over the spokes, 83b and permit support of the plunger on the base of the die.

For this type of die the grid, designated gener-' ally as- 88, comprises a U-shaped frame 89 which has its side rails resting upon a plate 90 that is held against endwise displacement in relation to the frame by frame shoulders 89a, 89b that engage the front and rear ends of the plate; The

plate 90 has a circular aperture which is counter- Aside from the specific features which have been referred to in connection withthe annular cavity charging grid, the design and operational features which were pointed out in connection with the first described grid apply to the annular cavity grid construction. Accordingly it is believed that the operationof the apparatus with annular type cavity will be clear without further description.

It is to be understood, in connection with the appended claims, that the specific procedures and forms of apparatus which have been described and explained are subject to modification in various respects; within the bounds of equivalency.

What is claimed is:

1. In the briquetting of finely dividedmaterial the method of charging the open-topped cavity of a flat-topped die body having a cavity bottom wall movable verticall within the side walls of the cavity, the said method comprising deliver-'- ing such material into the cells of a charging grid slidably supported on the top of the dierbody and having a plurality of cells open at their tops and bottoms, while the bottom wall of the die ing of the said bottom wall relative to the die bodyv '11 a and grid to cause a simultaneous gravity discharge and merging of material from the said plurality of grid cells into thedie cavity, and

material. 2

2. Apparatus for briquetting finely divided material to form wide bodies of uniform density, said apparatus comprising a fiat-topped die body structure shaped to form the side walls of a die cavity; means operable in cooperation with the side walls of the cavity to compress material therein, said means comprising a bottom cavity wall relatively movable within the cavity side walls between the top thereof and a positon corresponding to the full depth of the cavity; a

charging grid slidably mounted on the top of the die body for reciprocation from a loading zone at one side of the die cavity to a discharge position overlying the cavity and return, the grid having a plurality of cells open at top and bottom and with a width in the direction of the reciprocation much less than the width of the die cavity in the same direction so that a plurality of grid cells overlie the entire die cavity when the grid is in its said discharge position; means for delivering uncompacted material into the grid when it is in the loading zone; means constructed to effect the reciprocation of the loaded grid to its discharge position over the die cavity while the bottom wall of the cavity is level with the top of the die bod structure and thereafter return the grid to the loading zone; and means constructed to eiiect the lowering of the cavity bottom wall in relation to its side walls while the grid is .at rest in its discharge position.

3. Apparatus as claimed in claim 2 m which a press mechanism comprising fixed base and gumbo thereafter slidingthe grid over the top of the die body to leave the die cavity level .iull of merged 6. In apparatus for briquetting finely divide 1 material to form wide bodies of uniform density,

the combination of die mechanism comprising a fiat-topped die body structure shaped to form the side walls of an open-topped die cavity and; means operable in cooperation with the side walls of the cavity to compress material therein; a charging grid slidably mounted on' the top of the die body for reciprocation from a loading zone at one side of the die cavity to a discharge position over-lying the cavity and-return, the grid having a plurality of cells open at top and bottom with a width in the direction ofreciprocation much less than the width of the die cavity in a the same direction and great enough to' receive uncompacted material under gravity flow without bridging and to dischargesaid material by gravity; means for effecting the said reciprocation of the charging grid; and controllable means at the loading zone for delivering the uncompacted material into the grid cells at a substantially uniform predetermined rate of flow.

7. Apparatus as claimed in claim 6 in which the means for-delivering the uncompacted material into the grid cellscomprises a feed chute inclined upward at an angle smaller than will induce flow of the material under treatment and controllable means for vibrating the chute and causing fiow of the material.

8. Apparatus as claimed in claim 6 in which the means for delivering the uncompacted material into the grid cells comprises a feed chute inclined upward at 'an angle smaller than will induce flow of the material under treatment, supply means for maintaining a uniform head of material in the chute, and controllable means for :brating the chute and. causing flow of the marial.

9. Apparatus as claimed in claim 2 in which the die cavity is annular in horizontal section and the charging grid comprises a plate having head parts and a power actuated movable platen,

said die body structure and bottom wall and charging grid being removable from the press mechanism as a unit, and in which the relative movements of the die body structure, bottom wall, charging grid and press mechanism are controlled by a plurality of limit switches mounted on the die body structure and electrically connected to a separable connector plug.

5. In briquetting apparatus, the combination with press mechanism comprising fixed base and head parts and a power actuated movable platen; of a combined die and charging mechanism supported on and movable with the press platen and removable therefrom as a unit, said combined mechanism comprising a base, a fiat-topped die' body shaped to form the side walls of adie cavity, springs yieldingly supporting the die body on the die base, a die bottom wall supported by the an annularzone corresponding to the die cavity in size and slotted to form the grid cells, the said plate being relieved on its under side so. that only its slotted zone and a circular rib surroundiangl the zone bear against the top oi the die 10. Apparatus as claimed in claim 6 in which the die cavity is annular in horizontal section and the charging grid comprises a plate having an annular zone corresponding to the die cavity in size and slotted to form the grid'cells, the said plate being relieved on its under side so that only its slotted zone and a circular rib surrounding the zone bear against the top of the die body. SAMUEL K. WELLMAN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

